When I was studying abroad in Rome (20 years ago) a chef taught me how to make traditional Roman spaghetti alla carbonara. It uses only 5 simple ingredients: spaghetti, guanciale (cured pork jowl), pecorino Romano, pasture-raised eggs, and freshly ground black pepper. He commented on the American penchant for adding cream to the sauce, which he said "is blasphemy." So if you want the real deal, forgo the cream! But do reserve a little of the cooking water in case you need to loosen the sauce. The key is to temper, but not scramble the eggs, they cook in the residual heat of the pasta and combine with the fat from cooking the guanciale and the cheese to form a creamy, smooth sauce.
1 lb spaghetti
3 pasture-raised eggs
4 oz guanciale (jowl bacon), chopped
2/3 cup pecorino Romano cheese, grated
Freshly ground black pepper
Cook the chopped guanciale in a skillet until browned then set aside, do not drain the rendered fat!
Cook spaghetti according to package directions until al dente
Meanwhile whisk together eggs, pecorino, and a few good grindings of black pepper
Drain the spaghetti, reserving a quarter cup of pasta water
Toss pasta together with the guanciale and fat, then add the egg mixture, and toss making sure it coats all the noodles, keep it moving and do not scramble the eggs!
If the sauce is too thick thin it with a little reserved pasta water. You should not need to add salt, the guanciale and pecorino are both very salty.